/*
* Copyright (C) 2010 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package android.net;
import android.os.Parcel;
import android.os.Parcelable;
import android.util.Pair;
import java.net.Inet4Address;
import java.net.Inet6Address;
import java.net.InetAddress;
import java.net.InterfaceAddress;
import java.net.UnknownHostException;
import static android.system.OsConstants.IFA_F_DADFAILED;
import static android.system.OsConstants.IFA_F_DEPRECATED;
import static android.system.OsConstants.IFA_F_OPTIMISTIC;
import static android.system.OsConstants.IFA_F_TENTATIVE;
import static android.system.OsConstants.RT_SCOPE_HOST;
import static android.system.OsConstants.RT_SCOPE_LINK;
import static android.system.OsConstants.RT_SCOPE_SITE;
import static android.system.OsConstants.RT_SCOPE_UNIVERSE;
/**
* Identifies an IP address on a network link.
*
* A {@code LinkAddress} consists of:
* <ul>
* <li>An IP address and prefix length (e.g., {@code 2001:db8::1/64} or {@code 192.0.2.1/24}).
* The address must be unicast, as multicast addresses cannot be assigned to interfaces.
* <li>Address flags: A bitmask of {@code OsConstants.IFA_F_*} values representing properties
* of the address (e.g., {@code android.system.OsConstants.IFA_F_OPTIMISTIC}).
* <li>Address scope: One of the {@code OsConstants.IFA_F_*} values; defines the scope in which
* the address is unique (e.g.,
* {@code android.system.OsConstants.RT_SCOPE_LINK} or
* {@code android.system.OsConstants.RT_SCOPE_UNIVERSE}).
* </ul>
*/
public class LinkAddress implements Parcelable {
/**
* IPv4 or IPv6 address.
*/
private InetAddress address;
/**
* Prefix length.
*/
private int prefixLength;
/**
* Address flags. A bitmask of IFA_F_* values.
*/
private int flags;
/**
* Address scope. One of the RT_SCOPE_* constants.
*/
private int scope;
/**
* Utility function to determines the scope of a unicast address. Per RFC 4291 section 2.5 and
* RFC 6724 section 3.2.
* @hide
*/
static int scopeForUnicastAddress(InetAddress addr) {
if (addr.isAnyLocalAddress()) {
return RT_SCOPE_HOST;
}
if (addr.isLoopbackAddress() || addr.isLinkLocalAddress()) {
return RT_SCOPE_LINK;
}
// isSiteLocalAddress() returns true for private IPv4 addresses, but RFC 6724 section 3.2
// says that they are assigned global scope.
if (!(addr instanceof Inet4Address) && addr.isSiteLocalAddress()) {
return RT_SCOPE_SITE;
}
return RT_SCOPE_UNIVERSE;
}
/**
* Utility function to check if |address| is a Unique Local IPv6 Unicast Address
* (a.k.a. "ULA"; RFC 4193).
*
* Per RFC 4193 section 8, fc00::/7 identifies these addresses.
*/
private boolean isIPv6ULA() {
if (address != null && address instanceof Inet6Address) {
byte[] bytes = address.getAddress();
return ((bytes[0] & (byte)0xfc) == (byte)0xfc);
}
return false;
}
/**
* Utility function for the constructors.
*/
private void init(InetAddress address, int prefixLength, int flags, int scope) {
if (address == null ||
address.isMulticastAddress() ||
prefixLength < 0 ||
((address instanceof Inet4Address) && prefixLength > 32) ||
(prefixLength > 128)) {
throw new IllegalArgumentException("Bad LinkAddress params " + address +
"/" + prefixLength);
}
this.address = address;
this.prefixLength = prefixLength;
this.flags = flags;
this.scope = scope;
}
/**
* Constructs a new {@code LinkAddress} from an {@code InetAddress} and prefix length, with
* the specified flags and scope. Flags and scope are not checked for validity.
* @param address The IP address.
* @param prefixLength The prefix length.
* @param flags A bitmask of {@code IFA_F_*} values representing properties of the address.
* @param scope An integer defining the scope in which the address is unique (e.g.,
* {@link OsConstants#RT_SCOPE_LINK} or {@link OsConstants#RT_SCOPE_SITE}).
* @hide
*/
public LinkAddress(InetAddress address, int prefixLength, int flags, int scope) {
init(address, prefixLength, flags, scope);
}
/**
* Constructs a new {@code LinkAddress} from an {@code InetAddress} and a prefix length.
* The flags are set to zero and the scope is determined from the address.
* @param address The IP address.
* @param prefixLength The prefix length.
* @hide
*/
public LinkAddress(InetAddress address, int prefixLength) {
this(address, prefixLength, 0, 0);
this.scope = scopeForUnicastAddress(address);
}
/**
* Constructs a new {@code LinkAddress} from an {@code InterfaceAddress}.
* The flags are set to zero and the scope is determined from the address.
* @param interfaceAddress The interface address.
* @hide
*/
public LinkAddress(InterfaceAddress interfaceAddress) {
this(interfaceAddress.getAddress(),
interfaceAddress.getNetworkPrefixLength());
}
/**
* Constructs a new {@code LinkAddress} from a string such as "192.0.2.5/24" or
* "2001:db8::1/64". The flags are set to zero and the scope is determined from the address.
* @param string The string to parse.
* @hide
*/
public LinkAddress(String address) {
this(address, 0, 0);
this.scope = scopeForUnicastAddress(this.address);
}
/**
* Constructs a new {@code LinkAddress} from a string such as "192.0.2.5/24" or
* "2001:db8::1/64", with the specified flags and scope.
* @param string The string to parse.
* @param flags The address flags.
* @param scope The address scope.
* @hide
*/
public LinkAddress(String address, int flags, int scope) {
// This may throw an IllegalArgumentException; catching it is the caller's responsibility.
Pair<InetAddress, Integer> ipAndMask = NetworkUtils.parseIpAndMask(address);
init(ipAndMask.first, ipAndMask.second, flags, scope);
}
/**
* Returns a string representation of this address, such as "192.0.2.1/24" or "2001:db8::1/64".
* The string representation does not contain the flags and scope, just the address and prefix
* length.
*/
@Override
public String toString() {
return address.getHostAddress() + "/" + prefixLength;
}
/**
* Compares this {@code LinkAddress} instance against {@code obj}. Two addresses are equal if
* their address, prefix length, flags and scope are equal. Thus, for example, two addresses
* that have the same address and prefix length are not equal if one of them is deprecated and
* the other is not.
*
* @param obj the object to be tested for equality.
* @return {@code true} if both objects are equal, {@code false} otherwise.
*/
@Override
public boolean equals(Object obj) {
if (!(obj instanceof LinkAddress)) {
return false;
}
LinkAddress linkAddress = (LinkAddress) obj;
return this.address.equals(linkAddress.address) &&
this.prefixLength == linkAddress.prefixLength &&
this.flags == linkAddress.flags &&
this.scope == linkAddress.scope;
}
/**
* Returns a hashcode for this address.
*/
@Override
public int hashCode() {
return address.hashCode() + 11 * prefixLength + 19 * flags + 43 * scope;
}
/**
* Determines whether this {@code LinkAddress} and the provided {@code LinkAddress}
* represent the same address. Two {@code LinkAddresses} represent the same address
* if they have the same IP address and prefix length, even if their properties are
* different.
*
* @param other the {@code LinkAddress} to compare to.
* @return {@code true} if both objects have the same address and prefix length, {@code false}
* otherwise.
* @hide
*/
public boolean isSameAddressAs(LinkAddress other) {
return address.equals(other.address) && prefixLength == other.prefixLength;
}
/**
* Returns the {@link InetAddress} of this {@code LinkAddress}.
*/
public InetAddress getAddress() {
return address;
}
/**
* Returns the prefix length of this {@code LinkAddress}.
*/
public int getPrefixLength() {
return prefixLength;
}
/**
* Returns the prefix length of this {@code LinkAddress}.
* TODO: Delete all callers and remove in favour of getPrefixLength().
* @hide
*/
public int getNetworkPrefixLength() {
return getPrefixLength();
}
/**
* Returns the flags of this {@code LinkAddress}.
*/
public int getFlags() {
return flags;
}
/**
* Returns the scope of this {@code LinkAddress}.
*/
public int getScope() {
return scope;
}
/**
* Returns true if this {@code LinkAddress} is global scope and preferred.
* @hide
*/
public boolean isGlobalPreferred() {
/**
* Note that addresses flagged as IFA_F_OPTIMISTIC are
* simultaneously flagged as IFA_F_TENTATIVE (when the tentative
* state has cleared either DAD has succeeded or failed, and both
* flags are cleared regardless).
*/
return (scope == RT_SCOPE_UNIVERSE &&
!isIPv6ULA() &&
(flags & (IFA_F_DADFAILED | IFA_F_DEPRECATED)) == 0L &&
((flags & IFA_F_TENTATIVE) == 0L || (flags & IFA_F_OPTIMISTIC) != 0L));
}
/**
* Implement the Parcelable interface.
*/
public int describeContents() {
return 0;
}
/**
* Implement the Parcelable interface.
*/
public void writeToParcel(Parcel dest, int flags) {
dest.writeByteArray(address.getAddress());
dest.writeInt(prefixLength);
dest.writeInt(this.flags);
dest.writeInt(scope);
}
/**
* Implement the Parcelable interface.
*/
public static final Creator<LinkAddress> CREATOR =
new Creator<LinkAddress>() {
public LinkAddress createFromParcel(Parcel in) {
InetAddress address = null;
try {
address = InetAddress.getByAddress(in.createByteArray());
} catch (UnknownHostException e) {
// Nothing we can do here. When we call the constructor, we'll throw an
// IllegalArgumentException, because a LinkAddress can't have a null
// InetAddress.
}
int prefixLength = in.readInt();
int flags = in.readInt();
int scope = in.readInt();
return new LinkAddress(address, prefixLength, flags, scope);
}
public LinkAddress[] newArray(int size) {
return new LinkAddress[size];
}
};
}
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